CVE-2026-85873

Undergoing Analysis Undergoing Analysis - In Progress

Improper Authorization in Skype for Business and Microsoft Lync

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Improper authorization in Skype for Business and Microsoft Lync allows an authorized attacker to elevate privileges over a network.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-85873

EUVD

EUVD-2026-100142

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	Skype	for Business Server 2015 CU13 9319.0
Microsoft	Skype	for Business Server 2019 CU8 2046.0
Microsoft	Skype	for Business Server Subscription Edition CU1 2046.0
Microsoft	Skype	for Business Server Subscription Edition RTM 1.0.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-639	The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

Attack-Flow Graph

Executive Summary

This vulnerability is an improper authorization issue in Skype for Business and Microsoft Lync. An authorized attacker can exploit it over a network to elevate their privileges.

Impact Analysis

An attacker could gain higher access levels than intended, potentially allowing them to perform unauthorized actions or access sensitive data in affected systems.

Compliance Impact

This vulnerability allows an authorized attacker to elevate privileges over a network, which could lead to unauthorized access to sensitive communications and data. This may violate compliance requirements under GDPR (data protection) and HIPAA (health information privacy) by enabling unauthorized disclosure or modification of protected data.

Mitigation Strategies

Apply the latest security updates from Microsoft for Skype for Business Server and Microsoft Lync as soon as they become available.

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